1. Field of the Invention
This invention relates to a process for making a metal wall enclosure of a package to be used for accommodating electronic elements, such as a semiconductor chip or the like.
2. Prior Art
A metal package having a circumferential wall formed of metal has been conventionally known in the prior art, for use as a package for accommodating electronic elements. Such a metal package can be made by a first or a second process as mentioned below.
The first process comprises a step for mechanically machining a metal block to form an integral metal wall.
The second process comprises a step for cutting a cylindrical hollow tube having a rectangular cross-section into a ring-like shape having a sidewall of a predetermined axial height, forming an aperture in the hollow tube sidewall used for installing therein a ceramic terminal frame or the like, and thus forming the metal side wall of the enclosure. A metal bottom wall is hermetically attached to the bottom edge of the side wall, thereby to close the bottom, open end of the sidewall, as formed from the hollow tube.
However, according to the first process, a large amount of laborious work and time are required, since a metal block must be machined to form an integral metal wall.
According to the second process, a hole (i.e., an aperture in a pre-formed wall) which is used for installing a ceramic terminal frame or the like must be formed by an electric spark process, not by a punching process. Thus, a large amount of laborious work and time are also required.